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  <section id="set-objects">
<span id="setobjects"></span><h1>Set Objects<a class="headerlink" href="#set-objects" title="Permalink to this headline">¶</a></h1>
<p id="index-0">This section details the public API for <a class="reference internal" href="../library/stdtypes.html#set" title="set"><code class="xref py py-class docutils literal notranslate"><span class="pre">set</span></code></a> and <a class="reference internal" href="../library/stdtypes.html#frozenset" title="frozenset"><code class="xref py py-class docutils literal notranslate"><span class="pre">frozenset</span></code></a>
objects.  Any functionality not listed below is best accessed using the either
the abstract object protocol (including <a class="reference internal" href="call.html#c.PyObject_CallMethod" title="PyObject_CallMethod"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyObject_CallMethod()</span></code></a>,
<a class="reference internal" href="object.html#c.PyObject_RichCompareBool" title="PyObject_RichCompareBool"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyObject_RichCompareBool()</span></code></a>, <a class="reference internal" href="object.html#c.PyObject_Hash" title="PyObject_Hash"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyObject_Hash()</span></code></a>,
<a class="reference internal" href="object.html#c.PyObject_Repr" title="PyObject_Repr"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyObject_Repr()</span></code></a>, <a class="reference internal" href="object.html#c.PyObject_IsTrue" title="PyObject_IsTrue"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyObject_IsTrue()</span></code></a>, <a class="reference internal" href="object.html#c.PyObject_Print" title="PyObject_Print"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyObject_Print()</span></code></a>, and
<a class="reference internal" href="object.html#c.PyObject_GetIter" title="PyObject_GetIter"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyObject_GetIter()</span></code></a>) or the abstract number protocol (including
<a class="reference internal" href="number.html#c.PyNumber_And" title="PyNumber_And"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyNumber_And()</span></code></a>, <a class="reference internal" href="number.html#c.PyNumber_Subtract" title="PyNumber_Subtract"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyNumber_Subtract()</span></code></a>, <a class="reference internal" href="number.html#c.PyNumber_Or" title="PyNumber_Or"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyNumber_Or()</span></code></a>,
<a class="reference internal" href="number.html#c.PyNumber_Xor" title="PyNumber_Xor"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyNumber_Xor()</span></code></a>, <a class="reference internal" href="number.html#c.PyNumber_InPlaceAnd" title="PyNumber_InPlaceAnd"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyNumber_InPlaceAnd()</span></code></a>,
<a class="reference internal" href="number.html#c.PyNumber_InPlaceSubtract" title="PyNumber_InPlaceSubtract"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyNumber_InPlaceSubtract()</span></code></a>, <a class="reference internal" href="number.html#c.PyNumber_InPlaceOr" title="PyNumber_InPlaceOr"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyNumber_InPlaceOr()</span></code></a>, and
<a class="reference internal" href="number.html#c.PyNumber_InPlaceXor" title="PyNumber_InPlaceXor"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyNumber_InPlaceXor()</span></code></a>).</p>
<dl class="type">
<dt id="c.PySetObject">
<code class="sig-name descname">PySetObject</code><a class="headerlink" href="#c.PySetObject" title="Permalink to this definition">¶</a></dt>
<dd><p>This subtype of <a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><code class="xref c c-type docutils literal notranslate"><span class="pre">PyObject</span></code></a> is used to hold the internal data for both
<a class="reference internal" href="../library/stdtypes.html#set" title="set"><code class="xref py py-class docutils literal notranslate"><span class="pre">set</span></code></a> and <a class="reference internal" href="../library/stdtypes.html#frozenset" title="frozenset"><code class="xref py py-class docutils literal notranslate"><span class="pre">frozenset</span></code></a> objects.  It is like a <a class="reference internal" href="dict.html#c.PyDictObject" title="PyDictObject"><code class="xref c c-type docutils literal notranslate"><span class="pre">PyDictObject</span></code></a>
in that it is a fixed size for small sets (much like tuple storage) and will
point to a separate, variable sized block of memory for medium and large sized
sets (much like list storage). None of the fields of this structure should be
considered public and are subject to change.  All access should be done through
the documented API rather than by manipulating the values in the structure.</p>
</dd></dl>

<dl class="var">
<dt id="c.PySet_Type">
<a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject">PyTypeObject</a> <code class="sig-name descname">PySet_Type</code><a class="headerlink" href="#c.PySet_Type" title="Permalink to this definition">¶</a></dt>
<dd><p>This is an instance of <a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject"><code class="xref c c-type docutils literal notranslate"><span class="pre">PyTypeObject</span></code></a> representing the Python
<a class="reference internal" href="../library/stdtypes.html#set" title="set"><code class="xref py py-class docutils literal notranslate"><span class="pre">set</span></code></a> type.</p>
</dd></dl>

<dl class="var">
<dt id="c.PyFrozenSet_Type">
<a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject">PyTypeObject</a> <code class="sig-name descname">PyFrozenSet_Type</code><a class="headerlink" href="#c.PyFrozenSet_Type" title="Permalink to this definition">¶</a></dt>
<dd><p>This is an instance of <a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject"><code class="xref c c-type docutils literal notranslate"><span class="pre">PyTypeObject</span></code></a> representing the Python
<a class="reference internal" href="../library/stdtypes.html#frozenset" title="frozenset"><code class="xref py py-class docutils literal notranslate"><span class="pre">frozenset</span></code></a> type.</p>
</dd></dl>

<p>The following type check macros work on pointers to any Python object. Likewise,
the constructor functions work with any iterable Python object.</p>
<dl class="function">
<dt id="c.PySet_Check">
int <code class="sig-name descname">PySet_Check</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *p</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PySet_Check" title="Permalink to this definition">¶</a></dt>
<dd><p>Return true if <em>p</em> is a <a class="reference internal" href="../library/stdtypes.html#set" title="set"><code class="xref py py-class docutils literal notranslate"><span class="pre">set</span></code></a> object or an instance of a subtype.
This function always succeeds.</p>
</dd></dl>

<dl class="function">
<dt id="c.PyFrozenSet_Check">
int <code class="sig-name descname">PyFrozenSet_Check</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *p</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyFrozenSet_Check" title="Permalink to this definition">¶</a></dt>
<dd><p>Return true if <em>p</em> is a <a class="reference internal" href="../library/stdtypes.html#frozenset" title="frozenset"><code class="xref py py-class docutils literal notranslate"><span class="pre">frozenset</span></code></a> object or an instance of a
subtype.  This function always succeeds.</p>
</dd></dl>

<dl class="function">
<dt id="c.PyAnySet_Check">
int <code class="sig-name descname">PyAnySet_Check</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *p</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyAnySet_Check" title="Permalink to this definition">¶</a></dt>
<dd><p>Return true if <em>p</em> is a <a class="reference internal" href="../library/stdtypes.html#set" title="set"><code class="xref py py-class docutils literal notranslate"><span class="pre">set</span></code></a> object, a <a class="reference internal" href="../library/stdtypes.html#frozenset" title="frozenset"><code class="xref py py-class docutils literal notranslate"><span class="pre">frozenset</span></code></a> object, or an
instance of a subtype.  This function always succeeds.</p>
</dd></dl>

<dl class="function">
<dt id="c.PyAnySet_CheckExact">
int <code class="sig-name descname">PyAnySet_CheckExact</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *p</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyAnySet_CheckExact" title="Permalink to this definition">¶</a></dt>
<dd><p>Return true if <em>p</em> is a <a class="reference internal" href="../library/stdtypes.html#set" title="set"><code class="xref py py-class docutils literal notranslate"><span class="pre">set</span></code></a> object or a <a class="reference internal" href="../library/stdtypes.html#frozenset" title="frozenset"><code class="xref py py-class docutils literal notranslate"><span class="pre">frozenset</span></code></a> object but
not an instance of a subtype.  This function always succeeds.</p>
</dd></dl>

<dl class="function">
<dt id="c.PyFrozenSet_CheckExact">
int <code class="sig-name descname">PyFrozenSet_CheckExact</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *p</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyFrozenSet_CheckExact" title="Permalink to this definition">¶</a></dt>
<dd><p>Return true if <em>p</em> is a <a class="reference internal" href="../library/stdtypes.html#frozenset" title="frozenset"><code class="xref py py-class docutils literal notranslate"><span class="pre">frozenset</span></code></a> object but not an instance of a
subtype.  This function always succeeds.</p>
</dd></dl>

<dl class="function">
<dt id="c.PySet_New">
<a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a>* <code class="sig-name descname">PySet_New</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *iterable</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PySet_New" title="Permalink to this definition">¶</a></dt>
<dd><em class="refcount">Return value: New reference.</em><p>Return a new <a class="reference internal" href="../library/stdtypes.html#set" title="set"><code class="xref py py-class docutils literal notranslate"><span class="pre">set</span></code></a> containing objects returned by the <em>iterable</em>.  The
<em>iterable</em> may be <code class="docutils literal notranslate"><span class="pre">NULL</span></code> to create a new empty set.  Return the new set on
success or <code class="docutils literal notranslate"><span class="pre">NULL</span></code> on failure.  Raise <a class="reference internal" href="../library/exceptions.html#TypeError" title="TypeError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">TypeError</span></code></a> if <em>iterable</em> is not
actually iterable.  The constructor is also useful for copying a set
(<code class="docutils literal notranslate"><span class="pre">c=set(s)</span></code>).</p>
</dd></dl>

<dl class="function">
<dt id="c.PyFrozenSet_New">
<a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a>* <code class="sig-name descname">PyFrozenSet_New</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *iterable</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyFrozenSet_New" title="Permalink to this definition">¶</a></dt>
<dd><em class="refcount">Return value: New reference.</em><p>Return a new <a class="reference internal" href="../library/stdtypes.html#frozenset" title="frozenset"><code class="xref py py-class docutils literal notranslate"><span class="pre">frozenset</span></code></a> containing objects returned by the <em>iterable</em>.
The <em>iterable</em> may be <code class="docutils literal notranslate"><span class="pre">NULL</span></code> to create a new empty frozenset.  Return the new
set on success or <code class="docutils literal notranslate"><span class="pre">NULL</span></code> on failure.  Raise <a class="reference internal" href="../library/exceptions.html#TypeError" title="TypeError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">TypeError</span></code></a> if <em>iterable</em> is
not actually iterable.</p>
</dd></dl>

<p>The following functions and macros are available for instances of <a class="reference internal" href="../library/stdtypes.html#set" title="set"><code class="xref py py-class docutils literal notranslate"><span class="pre">set</span></code></a>
or <a class="reference internal" href="../library/stdtypes.html#frozenset" title="frozenset"><code class="xref py py-class docutils literal notranslate"><span class="pre">frozenset</span></code></a> or instances of their subtypes.</p>
<dl class="function">
<dt id="c.PySet_Size">
Py_ssize_t <code class="sig-name descname">PySet_Size</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *anyset</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PySet_Size" title="Permalink to this definition">¶</a></dt>
<dd><p id="index-1">Return the length of a <a class="reference internal" href="../library/stdtypes.html#set" title="set"><code class="xref py py-class docutils literal notranslate"><span class="pre">set</span></code></a> or <a class="reference internal" href="../library/stdtypes.html#frozenset" title="frozenset"><code class="xref py py-class docutils literal notranslate"><span class="pre">frozenset</span></code></a> object. Equivalent to
<code class="docutils literal notranslate"><span class="pre">len(anyset)</span></code>.  Raises a <code class="xref py py-exc docutils literal notranslate"><span class="pre">PyExc_SystemError</span></code> if <em>anyset</em> is not a
<a class="reference internal" href="../library/stdtypes.html#set" title="set"><code class="xref py py-class docutils literal notranslate"><span class="pre">set</span></code></a>, <a class="reference internal" href="../library/stdtypes.html#frozenset" title="frozenset"><code class="xref py py-class docutils literal notranslate"><span class="pre">frozenset</span></code></a>, or an instance of a subtype.</p>
</dd></dl>

<dl class="function">
<dt id="c.PySet_GET_SIZE">
Py_ssize_t <code class="sig-name descname">PySet_GET_SIZE</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *anyset</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PySet_GET_SIZE" title="Permalink to this definition">¶</a></dt>
<dd><p>Macro form of <a class="reference internal" href="#c.PySet_Size" title="PySet_Size"><code class="xref c c-func docutils literal notranslate"><span class="pre">PySet_Size()</span></code></a> without error checking.</p>
</dd></dl>

<dl class="function">
<dt id="c.PySet_Contains">
int <code class="sig-name descname">PySet_Contains</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *anyset</em>, <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *key</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PySet_Contains" title="Permalink to this definition">¶</a></dt>
<dd><p>Return <code class="docutils literal notranslate"><span class="pre">1</span></code> if found, <code class="docutils literal notranslate"><span class="pre">0</span></code> if not found, and <code class="docutils literal notranslate"><span class="pre">-1</span></code> if an error is encountered.  Unlike
the Python <a class="reference internal" href="../reference/datamodel.html#object.__contains__" title="object.__contains__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__contains__()</span></code></a> method, this function does not automatically
convert unhashable sets into temporary frozensets.  Raise a <a class="reference internal" href="../library/exceptions.html#TypeError" title="TypeError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">TypeError</span></code></a> if
the <em>key</em> is unhashable. Raise <code class="xref py py-exc docutils literal notranslate"><span class="pre">PyExc_SystemError</span></code> if <em>anyset</em> is not a
<a class="reference internal" href="../library/stdtypes.html#set" title="set"><code class="xref py py-class docutils literal notranslate"><span class="pre">set</span></code></a>, <a class="reference internal" href="../library/stdtypes.html#frozenset" title="frozenset"><code class="xref py py-class docutils literal notranslate"><span class="pre">frozenset</span></code></a>, or an instance of a subtype.</p>
</dd></dl>

<dl class="function">
<dt id="c.PySet_Add">
int <code class="sig-name descname">PySet_Add</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *set</em>, <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *key</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PySet_Add" title="Permalink to this definition">¶</a></dt>
<dd><p>Add <em>key</em> to a <a class="reference internal" href="../library/stdtypes.html#set" title="set"><code class="xref py py-class docutils literal notranslate"><span class="pre">set</span></code></a> instance.  Also works with <a class="reference internal" href="../library/stdtypes.html#frozenset" title="frozenset"><code class="xref py py-class docutils literal notranslate"><span class="pre">frozenset</span></code></a>
instances (like <a class="reference internal" href="tuple.html#c.PyTuple_SetItem" title="PyTuple_SetItem"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyTuple_SetItem()</span></code></a> it can be used to fill-in the values
of brand new frozensets before they are exposed to other code).  Return <code class="docutils literal notranslate"><span class="pre">0</span></code> on
success or <code class="docutils literal notranslate"><span class="pre">-1</span></code> on failure. Raise a <a class="reference internal" href="../library/exceptions.html#TypeError" title="TypeError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">TypeError</span></code></a> if the <em>key</em> is
unhashable. Raise a <a class="reference internal" href="../library/exceptions.html#MemoryError" title="MemoryError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">MemoryError</span></code></a> if there is no room to grow.  Raise a
<a class="reference internal" href="../library/exceptions.html#SystemError" title="SystemError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">SystemError</span></code></a> if <em>set</em> is not an instance of <a class="reference internal" href="../library/stdtypes.html#set" title="set"><code class="xref py py-class docutils literal notranslate"><span class="pre">set</span></code></a> or its
subtype.</p>
</dd></dl>

<p>The following functions are available for instances of <a class="reference internal" href="../library/stdtypes.html#set" title="set"><code class="xref py py-class docutils literal notranslate"><span class="pre">set</span></code></a> or its
subtypes but not for instances of <a class="reference internal" href="../library/stdtypes.html#frozenset" title="frozenset"><code class="xref py py-class docutils literal notranslate"><span class="pre">frozenset</span></code></a> or its subtypes.</p>
<dl class="function">
<dt id="c.PySet_Discard">
int <code class="sig-name descname">PySet_Discard</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *set</em>, <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *key</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PySet_Discard" title="Permalink to this definition">¶</a></dt>
<dd><p>Return <code class="docutils literal notranslate"><span class="pre">1</span></code> if found and removed, <code class="docutils literal notranslate"><span class="pre">0</span></code> if not found (no action taken), and <code class="docutils literal notranslate"><span class="pre">-1</span></code> if an
error is encountered.  Does not raise <a class="reference internal" href="../library/exceptions.html#KeyError" title="KeyError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">KeyError</span></code></a> for missing keys.  Raise a
<a class="reference internal" href="../library/exceptions.html#TypeError" title="TypeError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">TypeError</span></code></a> if the <em>key</em> is unhashable.  Unlike the Python <code class="xref py py-meth docutils literal notranslate"><span class="pre">discard()</span></code>
method, this function does not automatically convert unhashable sets into
temporary frozensets. Raise <code class="xref py py-exc docutils literal notranslate"><span class="pre">PyExc_SystemError</span></code> if <em>set</em> is not an
instance of <a class="reference internal" href="../library/stdtypes.html#set" title="set"><code class="xref py py-class docutils literal notranslate"><span class="pre">set</span></code></a> or its subtype.</p>
</dd></dl>

<dl class="function">
<dt id="c.PySet_Pop">
<a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a>* <code class="sig-name descname">PySet_Pop</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *set</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PySet_Pop" title="Permalink to this definition">¶</a></dt>
<dd><em class="refcount">Return value: New reference.</em><p>Return a new reference to an arbitrary object in the <em>set</em>, and removes the
object from the <em>set</em>.  Return <code class="docutils literal notranslate"><span class="pre">NULL</span></code> on failure.  Raise <a class="reference internal" href="../library/exceptions.html#KeyError" title="KeyError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">KeyError</span></code></a> if the
set is empty. Raise a <a class="reference internal" href="../library/exceptions.html#SystemError" title="SystemError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">SystemError</span></code></a> if <em>set</em> is not an instance of
<a class="reference internal" href="../library/stdtypes.html#set" title="set"><code class="xref py py-class docutils literal notranslate"><span class="pre">set</span></code></a> or its subtype.</p>
</dd></dl>

<dl class="function">
<dt id="c.PySet_Clear">
int <code class="sig-name descname">PySet_Clear</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *set</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PySet_Clear" title="Permalink to this definition">¶</a></dt>
<dd><p>Empty an existing set of all elements.</p>
</dd></dl>

</section>


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